- 10 Rates Of Fairly Fast Reactions Can Be Determined Using Spectroscopy If One Of The Products Or Reactants Is A Colored 1 (166.9 KiB) Viewed 30 times
10. Rates of fairly fast reactions can be determined using spectroscopy if one of the products or reactants is a colored species. The following data was obtained while monitoring one such reaction. 10 20 30 40 50 60 70 80 Time (s) Absorbance 0.263 0.230 0.200 0.173 0.153 0.132 0.114 0.099 Order: Time (s) Absorbance [CV+] 0.263 0.230 0.200 0.173 0.153 0.132 0.114 0.099 0.086 0.076 0.067 0.057 0.051 0.045 0.039 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 The reaction was run in a 1 cm sample cell, and the absorptivity coefficient, &, for the colored compound is 94000M-¹cm-¹. In excel, or your graphing program of choice, calculate the concentrations for each data point and determine the order of the reaction graphically, as well as the value of the rate constant (with correct units). Turn in all three plots you can make to determine the order, as well as your table of data you used (you will probably want to retype the data in excel in a normal orientation, I transposed the data here to take up less space on the page). If you arrange your data and graphs in excel as given below, you can take a screen clip of them and just paste it into this document, or print that page as a pdf (make sure everything is on ONE page though if you print) and merge it to your homework pdf. Rate constant: First Order Graph ? 90 100 110 0.076 0.086 0.067 ? Beaulac Zero Order Graph Second Order Graph 120 150 130 140 0.045 0.039 0.051 0.057